A railway vehicle is a special vehicle operating on special rails, and when operating along the special rails, the railway vehicle can be self-oriented without being controlled in direction. A bogie is one of the most important components on the railway vehicle, and it supports the weight of an entire commodity and the weight of the vehicle body. The traditional bogies is mostly of a structure with three large parts, namely, two side frame components and a swing bolster component, guide frames on both ends of the side frame components are installed on front and back wheel pair components through axle box bearing saddles and bearing devices, and both ends of the swing bolster component are installed in central square frames of the side frame components through two groups of central suspension devices. The axle box bearing saddles and the bearing devices are movable joints contacting the side frame components with the wheel pair components, are used for converting rolling of wheels along the rail route into translation of the vehicle body along the rail route, and can flexibly operate along a straight line and successfully pass by a curve.
When the railway vehicle operates at a high speed on the rails, complex impact and vibration will be produced accordingly. A traditional axle box bearing saddle and the guide frames on both ends of the side frame component adopt a rigid connection structure, which has the defects that the axle box bearing saddle and the guide frames of the side frame are rigidly positioned in a dry friction manner, the frictional force increases linearly to fail to adapt to the high-speed operation demand of the vehicle, moreover the lateral force of wheel rails is large, and thus the risk of train derailment is increased. In order to reduce a variety of dynamic effects of unsmooth rail routes and high speed motion of wheel pairs on the vehicle body, for example, longitudinal impact, vertical vibration, lateral vibration and the like, those skilled in the art often additionally set an elastic device between the guide frame of the side frame and the wheel pair component of the railway vehicle bogie, and the elastic device is generally called an elastic axle box suspension device. The elastic axle box suspension device plays an important role in such aspects as whether the linear operation of the vehicle is stable, whether the vehicle can successfully pass by the curve, and guaranteeing the safe operation of the vehicle, and the like.
With the continuous increase of the load capacity of the railway vehicle, the axle weight of the vehicle increases constantly, and the operation speed of the vehicle is continuously improved, so that the requirements on the quality and performance of the vehicle bogie is also higher and higher. At a state of heavy load and high speed, when moving along the rails, the vehicle wheel pairs are easier to initiate yaw motion of the vehicle body, resulting in greatly reduced operation quality of the vehicle and will cause a vehicle derailment accident seriously. Meanwhile, when the vehicle passes by the curve, the lateral force of the wheel rail cannot be too large, otherwise, the vehicle is also possible to derail. One of the critical components directly affecting the snaking critical operation speed of the railway vehicle on a straight line and the passing performance of the vehicle on a curve is the elastic axle box suspension device, and the structural shape design and the elastic stiffness parameter design thereof are of vital importance. In order to increase the snaking critical operation speed of the railway vehicle on the straight line, larger longitudinal positioning stiffness of the elastic axle box suspension device must be required; when the vehicle passes by the curve, to prevent an over large lateral force of the wheel rail, a smaller longitudinal positioning stiffness of the elastic axle box suspension device must be required.
At present, improving the snaking critical operation speed of the vehicle on the straight line and improving the passing performance of the vehicle on the curve are a pair of contradictions, and thus it is very hard to give consideration to both in the specific design of the elastic axle box suspension device of the vehicle bogie. This is because, two main elastic axle box suspension devices cannot simultaneously satisfy the above-mentioned requirements at present: one is a vertical elastic device arranged between the top face of the axle box bearing saddle and the bottom surface of the guide frame of the side frame, although the device has a certain function on vertical damping of the bogie, the axle box bearing saddle is in rigid hard contact with the bottom surface of the guide frame of the side frame, and no buffering device is available, so that the inhibitory effect on lateral vibration and longitudinal vibration of the bogie is poor, moreover the structural design is quite complex, the parameter matching difficulty is very large, the assembly universality is poor, and the snaking critical operation speed of the vehicle on the straight line and the passing performance requirement of the vehicle on the curve cannot be compromised in the case of acceleration and heavy load. Another condition is that a vertical elastic device is arranged, and longitudinal elastic devices are arranged between the axle box bearing saddle and both sides of the guide frame of the side frame, in this way, damping and control on the longitudinal impact of the bogie are easier to achieve, but the stiffness of the front and back longitudinal elastic devices are invariable, due to the limitation of this structural form, with the increase of the displacement, the load of the bogie increases linearly or in an equal proportional increase manner, the snaking critical operation speed of the vehicle on the straight line and the passing performance requirement of the vehicle on the curve cannot be completely compromised either, and meanwhile the risk of train derailment also exists, so that the functions of the elastic axle box suspension device are greatly reduced.
How to effectively improve the linear stability and the curve passing performance of the heavy-loaded vehicle operates at a high speed is always a problem attempted to be solved by those skilled in the art, and this has important practical significance of improving the operation quality of the railway vehicle and guaranteeing the safety performance of the railway vehicle.